Field of Invention
The present invention relates to an electrical connector. More particularly, the present invention relates to an electrical connector for transmitting high-frequency signal.
Description of Related Art
Due to the highly development of technologies, to provide various transmission requirement, several transmission specifications are introduced, such as the early Small Computer System Interface (SCSI) to the latest Serial Attached SCSI (SAS). For a high speed data access, the serial technologies solve the problem in the traditional parallel technologies, providing further high speed signal transmission. Therefore, the SAS can be support of and compatible with Serial Advanced Technology Attachment (SATA) device, resulting in advantages of wider use.
Under the requirements of high speed transmission and reduced size of electrical connectors, the arrangement between terminals becomes closer, and the signal transmission becomes high-frequency transmission. Therefore, issues such as signal interference are generated when the connector transmits signals. Since the distance between two signal terminals is too close, capacitive and inductive couplings are induced between signal terminals when high-frequency signals are transmitted. The capacitive and inductive couplings lead to the problem of cross talk and noise, thereby affecting the transmission rate and accuracy.
To overcome the problem of cross talk, in conventional technology, a ground terminal is disposed between two signal terminals. The ground terminal can ground the capacitive and inductive noises coupled by the signal terminals, thereby reducing the signal interference. However, such technology for solving cross talk interference still remains a lot to improve.
To improve the problem of cross talk, U.S. Pat. No. 2013/0149882 discloses an electrical connector, as shown in FIG. 11. The electrical connector includes a housing A, a plurality of contacts B and a ground bar C. The housing A is made of insulating material. The contacts B and the ground bar C are disposed in the housing A. The housing A includes a base portion A1 and a tongue portion A2 extended from the base portion A1. The contacts B include a plurality of grounding portions B1 and a plurality of signal contacts (not shown). The grounding portions B1 respectively include a contacting plate B11, a soldering portion B13, and a retaining portion B12 connecting the contacting plate B11 to the soldering portion B13. The contacting plates B11 are arranged on a plane of the tongue portion A2. The retaining portion B12 is disposed in the base portion A1. The ends of the soldering portion B13 respectively extend out of the base portion A1, and the solder portion B13 may be connected to a circuit board (not shown). The arrangement of the contacts B includes one signal contact (not shown) disposed between at least two of the grounding portions B1. The ground bar C includes a plurality of spring fingers C1 and a beam portion C2. The spring fingers C1 extend from the beam portion C2 and are electrically connected to each other. The spring fingers C1 contact the retaining portion B12 of the grounding portions B1 and are disposed in the housing A.
In the prior art, the grounding portions B1 are connected to the spring fingers C1 of the ground bar C, such that the noises induced by the high-frequency transmission signal of the signal contacts (not shown) may be grounded, thereby reducing the problem of cross talk.
However, in the prior art, the grounding portions B1 are connected to the ground bar C through one of the corresponding spring fingers C1, and the contact area between the retaining portion B12 of the grounding portions B1 and the spring fingers C1 is small. When the interference noises are grounded through the grounding portion B1 and the ground bar C, the transmission rate of grounding noises is lower due to the small contact area. Therefore, the problem of high-frequency interference still exists in the electrical connector. Moreover, during the assembling process of spring fingers C1 and the grounding portions B1, the registration yield and the adherence condition are both factors that affect the grounding of interference.
Since that the prior art cannot satisfy the practical requirement of industry, an improvement is needed to overcome the problem.